From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:47448 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966039AbbJWAsT (ORCPT ); Thu, 22 Oct 2015 20:48:19 -0400 Subject: Patch "net: add pfmemalloc check in sk_add_backlog()" has been added to the 4.2-stable tree To: edumazet@google.com, davem@davemloft.net, gregkh@linuxfoundation.org, gthelen@google.com Cc: , From: Date: Thu, 22 Oct 2015 17:48:17 -0700 Message-ID: <14455612977838@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled net: add pfmemalloc check in sk_add_backlog() to the 4.2-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-add-pfmemalloc-check-in-sk_add_backlog.patch and it can be found in the queue-4.2 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Thu Oct 22 17:25:24 PDT 2015 From: Eric Dumazet Date: Tue, 29 Sep 2015 18:52:25 -0700 Subject: net: add pfmemalloc check in sk_add_backlog() From: Eric Dumazet [ Upstream commit c7c49b8fde26b74277188bdc6c9dca38db6fa35b ] Greg reported crashes hitting the following check in __sk_backlog_rcv() BUG_ON(!sock_flag(sk, SOCK_MEMALLOC)); The pfmemalloc bit is currently checked in sk_filter(). This works correctly for TCP, because sk_filter() is ran in tcp_v[46]_rcv() before hitting the prequeue or backlog checks. For UDP or other protocols, this does not work, because the sk_filter() is ran from sock_queue_rcv_skb(), which might be called _after_ backlog queuing if socket is owned by user by the time packet is processed by softirq handler. Fixes: b4b9e35585089 ("netvm: set PF_MEMALLOC as appropriate during SKB processing") Signed-off-by: Eric Dumazet Reported-by: Greg Thelen Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/net/sock.h | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/include/net/sock.h +++ b/include/net/sock.h @@ -826,6 +826,14 @@ static inline __must_check int sk_add_ba if (sk_rcvqueues_full(sk, limit)) return -ENOBUFS; + /* + * If the skb was allocated from pfmemalloc reserves, only + * allow SOCK_MEMALLOC sockets to use it as this socket is + * helping free memory + */ + if (skb_pfmemalloc(skb) && !sock_flag(sk, SOCK_MEMALLOC)) + return -ENOMEM; + __sk_add_backlog(sk, skb); sk->sk_backlog.len += skb->truesize; return 0; Patches currently in stable-queue which might be from edumazet@google.com are queue-4.2/inet-fix-races-in-reqsk_queue_hash_req.patch queue-4.2/net-add-pfmemalloc-check-in-sk_add_backlog.patch queue-4.2/inet-fix-race-in-reqsk_queue_unlink.patch queue-4.2/net-unix-fix-logic-about-sk_peek_offset.patch queue-4.2/act_mirred-clear-sender-cpu-before-sending-to-tx.patch